MINERALOGICAL AND WALLROCK ALTERATION AT THE JINQINGDING GOLD DEPOSITIN JIAODONG PENINSULA, CHINA

The Jinqingding gold deposit, situated in the east Jiaodong Peninsula of Shandong province, is typical of the pyrite-quartz vein gold deposi ts in the Muping-Rushan gold belt of China. The gold deposit is contro lled by a great NNE fracture zone and is composed of several lenticula r orebodies within the fracture zone occurring in the Kunyushan granit e massif. The Kunyushan granite massif was formed by the replacement o f the Archean Jiaodong group. The main minerals associated with gold a re pyrite, chalcopyrite, galena and sphalerite; the gangue minerals ar e dominated by quartz, sericite, microcline and calcite. The mineraliz ing event can be divided into four stages: (1) pyrite-quartz; (2) quar tz-pyrite; (3) siderite-polymetallic sulfides; and (4) calcite-quartz. Gold occurs mainly as native gold and electrum in stage I and stage I I. There are some evident differences between pyrite from major stages of gold mineralization and that from minor stages; these include diff erences in crystal forms, size and composition of fluid inclusions. Wa llrock alterations consist of sericitization, silicification, pyritiza tion and potash-feldspar alteration. Five alteration zones can be dist inguished from unaltered granite (zone 0) to vein lodes (zone IV). Au and Ag increase rapidly from zone 0 to zone IV, Cu increases continuou sly, while Pb and Zn increase slowly. R-type geological factor analysi s indicates that the Au, Ag, Cu, Pb and Zn bear a close relationship t o wallrock alteration.